Throwback Thursday: What is a variable star? (Synopsis)

“To be is to be the value of a variable.” –Willard Van Orman Quine

Those constant, fixed points of light in the night sky — the stars — turn out not to be so constant if you looked with great precision at them. A star like our Sun varies in brightness, periodically, by about 0.1% over the span of a few years, but many stars vary by 99% or more from brightest to dimmest.

Image credit: British Astronomical Association Variable Star Section, via http://www.britastro.org/vss/.
Image credit: British Astronomical Association Variable Star Section, via http://www.britastro.org/vss/.

For centuries, we knew of only a handful of these objects, yet now they’re known to be commonplace. What causes this spectacular behavior, how did we discover it and what’s the physical mechanism underlying it?

Image credit: NASA, ESA and A. Nota (STScI/ESA).
Image credit: NASA, ESA and A. Nota (STScI/ESA).

Come learn about the science of variable stars on this edition of Throwback Thursday!

4 thoughts on “Throwback Thursday: What is a variable star? (Synopsis)”

  1. Well, as far as I’m aware, there are three types of variable.

    Inherently variable. Stars that change their luminosity.

    Multistar variables. Objects that change their luminosity because they appear to be a singe object when they are not.

    Occulted variables. Stars that have their brightness changed by having something dark move in front of them.

Comments are closed.